knock sensor gone bad?

dac69er

Super Moderator
for no reason that i can find, every time i take my car out the knock readings appear to get higher and higher and higher!

tonight i got a reading of >60, i normally get a max of 30 if that.

fuelling is ok, looking at the wideband, there is no issue and is fuelling the same as always.

has anyone ever had a knock sensor go bad? obviously it is possible, just wondered if anyone had experienced it before!?
 

Skalabala

Member +
I cant talk for 4EFTE but on other cars yes they do go bad.
Can you hear knock at all? And does it pull away timing?
 

Jay

Admin
I don't have anything that measures knock so the only time I've noticed a dead knock sensor is when the engine lamp has flashed up. Might be worth swapping in another unit just to see what difference it makes.
 

dac69er

Super Moderator
I cant talk for 4EFTE but on other cars yes they do go bad.
Can you hear knock at all? And does it pull away timing?

its on a power fc so wont pull back the timing. it has always read higher than my ep85 that is also running a power fc, it has just got a lot worse lately.

i couldnt hear any knock, but tbh, if its bad enough to hear, it wouldnt last long!


i have swapped it with a spare new unit a bought ages ago and it reads lower already. its dark and wet now so will have to take it out another day and see what happens.

thanks
Duncan
 

Skalabala

Member +
If you can hear knock it means turn off engine :p
I have no experience with your management. Is it a stand alone?
This side of the world we do not use knock sensor on modified cars.
We use this on dyno :p
detcans2.jpg

Also make sure the wires are perfect all the way to the ECU
 

dac69er

Super Moderator
you must have heard of an apexi power fc!!!! yes it is stand alone.

took it out today with the new knock sensor and it appears to work ok. get really low readings. max i got was 10, but my car is hardly highly tuned.

i could do with taking it back to the dyno. just dont know of anyone who is any good.
 

Vic-GT

Fresh Recruit
good topic, on your case seem to be a faulty sensor right? I use to get high readings when my car was un-tuned once I adjusted timing and set correct values for air fuel mixture went down considerably.

One thing I have also notice is that weather condition will affect readings, my country is really hot and humid so readings will always be around 15- 20sh even though the car has already been tuned

cheers
 

dac69er

Super Moderator
Are you using a power fc to get your knock sensor readings?

It has always read on the higher side, but over time it has got higher and higher without me changing anything on the car. This year it has got really bad quite quickly and after I got a few really high readings I thought it was best to try and change the sensor.

I will try and get it checked on a dyno to make sure I am definitely not getting knock.
I might even change the sensor on my other starlets just to be 100% sure they are fine.
 

dac69er

Super Moderator
just a quick update.

wasnt happy with the really low readings as they just didnt seem right. i bought another knock sensor which matched the part number for the starlet and it is a bit more realistic now.

the face of the sensor also better matches the original.

got a maximum of about 20-25 on my knock reading, which is about what i used to get before the sensor went funny. its a little on the lower side, but the old sensor may have been going bad for a while.


going to get another as a spare as it was relatively cheap. not sure why the other sensor was slightly different? i cant see why toyota would have a range of sensor with exactly the same fitment?
 

dac69er

Super Moderator
just a quick update.

wasnt happy with the really low readings as they just didnt seem right. i bought another knock sensor which matched the part number for the starlet and it is a bit more realistic now.

the face of the sensor also better matches the original.

got a maximum of about 20-25 on my knock reading, which is about what i used to get before the sensor went funny. its a little on the lower side, but the old sensor may have been going bad for a while.


going to get another as a spare as it was relatively cheap. not sure why the other sensor was slightly different? i cant see why toyota would have a range of sensor with exactly the same fitment?
 

Jay

Admin
I'd imagine the noise the sensor listens for could differ depending on the thickness of the block. For example the frequency would differ between a 4e block and a 3sge block due to the physical differences.
 

dac69er

Super Moderator
I'd imagine the noise the sensor listens for could differ depending on the thickness of the block. For example the frequency would differ between a 4e block and a 3sge block due to the physical differences.

looking at part numbers it does appear that the knock sensors are suited to a certain range of engine. i think all the E series engines have the same knock sensor, whether turbo or n/a.

the one i got, although aftermarket, was specced as being a replacement for the correct part number for mine, so should be fine. as it gives similar knock readings to what i expected, it cant be far wrong.
 
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